A calculator is only useful if its answer is right. This page explains where our rules come from, how we test them and how often we update them.
Where the rules come from
We take each rule from a primary document wherever one is available:
- Income tax: the Finance Acts and FBR withholding tax rate cards.
- Electricity and gas: NEPRA tariff decisions and the SROs that notify them, plus monthly and quarterly adjustment decisions.
- University grades: each university's own regulations, handbooks and grading tables.
- Admissions: PMDC regulations and each university's admission notices and prospectus.
- Zakat: the official zakat nisab notification for bank deductions.
Sometimes no primary document is online. In that case we use the best secondary source we can find, and the page says so plainly. For example, a grading page may say the table comes from a university's own student portal rather than a published regulation.
How we test each calculator
Each calculator is checked against worked examples before it goes live.
- Electricity: our bill calculator reproduces a real LESCO bill of 228 units from April 2026 to within a rupee, line by line. That includes the energy charge, fixed charge, fuel and quarterly adjustments, electricity duty and sales tax.
- Income tax: the slabs are checked at every boundary. We test the last rupee of one slab and the first rupee of the next, so the tax never jumps where it should not.
- Grades and aggregates: we test each formula with examples from the university's own documents where they give any, and with simple hand-worked cases where they do not.
Review dates
Each page shows a "last reviewed" date. That is the day we last checked the page against its sources, not just the day we edited the text.
How often rates are updated
| What | How often it changes |
|---|---|
| Income tax slabs | Each federal budget, usually from 1 July |
| Electricity fuel adjustment | Monthly |
| Electricity quarterly adjustment | Every three months |
| Electricity base tariff | Each January |
| Admission formulas | Each admission intake |
| Zakat bank nisab | Each Ramadan |
We update a page once the new rate is officially notified, not when it is first reported as a proposal.
Limits
Our results are estimates. A real bill can include items we cannot see, such as arrears, instalments or a local charge. A tax notice can reflect income or credits the calculator does not ask about. Where our figure differs from an official document, the official document is correct. If you think our rule is wrong, please tell us through the contact page.
Last updated 29 September 2026